Thermostatically-adjusted scale lever



July 8 1924. 0 1,500,405

G. M. LUDLOW THERHOSTATICALLY ADJUSTED SCALE LEVER Filed Jun 4. 1923 g J 2 1 A I 1 4 I i v 0 o jzuezzZor $607 $6664 50a) Patented July 8, 1924. Ti

UNITED STATES' PATENT OF F l C E GEORGE M. LUDLOW, OF EVANSTON, ILLINOIS, ASSIGNOR TO SANITARY SCALE COM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

THERMOSTATIOALLY-ADJUSTED SCALE LEVER.

Application filed June 4,

To all whom it may concern Be it known that I, Gnonon M. LUDLOW, a citizen of the United States, residing at Evanston, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Thermostaticallv Adjusted Scale Levers, of which the following is a specification.

This invention relates to scale levers through means of which the load to be weighed is transmitted to counter-balancing and load indicating mechanism, and particularly to scale levers of the type in which the length of the transmitting lever is auto-- matically varied to compensate for the effect of changes in temperature upon the counterbalancing mechanism or other scale parts.

It has been customary to equip levers of this type with a toe piece mounted upon the motion transmitting end of the lever in position to rest in a stirrup depending fron a steelyard rod or equivalent motion transmitting connector, and to automatically adjust this toe piece in the direction of the length of the lever and thereby vary the leverage and consequent weighing effect by means of a thermostat, a number of different forms of which have proven satisfactory in prac tice; and in order that the adjustable toe piece may, on the one hand, be prevented from unduly resisting and therefore detracting from the etficiency of the thermostatic action, and on the other hand be confined against lateral displacement on the lever, it has been proposed to sustain the toe piece against the lever by means of a plate carrying bearing balls of relatively small proportions over a relatively wide area of the plate and at the same time to provide confining pins, fingers, or the like at the sides of the toe piece. But this arrangement while affording a measure of satisfaction when new or so long as it is kept in proper condition, is nevertheless intricate and expensive and is subject to serious impairment in its operation if neglected.

Now, the object of the present invention is to provide a very simple, cheap, eflicient, and

lasting adjustable toe piece mounting forlevers of the kind described, and the invention proceeds upon the principle of providing between the lever and the adjustable toe piece a bearing embodying the essential characteristics of a ridge "and a groove extending in the direction of the toe piece ad- 1923. Serial No. 643,149.

justment and therefore in the direction of length of the lever, and with relative sliding movement between the ridge and the groove in said direction, but with resistance to relative movement transversely thereto, so that if one of said elements is carried by the toe piece and the other by the lever, frictional resistance to adjustment of the toe piece will be reduced to a minimum, the toe piece will be accurately confined in the line of its movement and against lateral displacement, the toe piece can rock to the limited degree necessary to insure proper stepping of the toe piece in the motion transmitting connector (usually through the medium of a knife edge transverse to the lever), and all impairment of function or structure of the toe piece bearing is insured against. In constructing the bearing surfaces, the one provided by the ridge will be formed on a relatively small radius or by two siees meeting at a relatively small angle, and the bearing surface provided by the groove will be formed on a larger radius or by sides meeting at a greater angle, so that the transverse dimension of the bearing is very small, or, theoretically, but a line. Preferably, the groove-carrying member of the bearing between the lever and the toe piece will be agate or equivalent mineral substance, and will be mounted on the lever, while the toe piece is of hard steel and shaped to provide the coacting ridge.

In the accompanying drawings.'

Figure 1 is a side elevation'of the lever system of a platform scale devised prior to the present invention, and to which the present invention is applied.

Figure 2 is a bottom plan view of the main lever of the system shown in Figure 1.

Figures 3, at, and 5, respectively, show on an enlarged scale, a vertical longitudinal section, a bottom plan view, and an end elevation of the left end portion of the lever shown in Figures 1 and 2.

Referring to Figures 1 and 2, 1 repre sents a scale lever having at one end fulcruining knives 2 and at its other end a load transmitting toe piece 3 through which it rests in a motion transmitting connector 4 in the form of a stirrup depending from a steelyard rod 5 or other weighing connection. It has heretofore been customary to mount the toe piece 3 so that it can be moved longitudinally of the lever 1 by means of some suitable form of thermostatic device, such, for instance, as the rod 6 connected at one end with toe piece 3 and having pivotal support 6 at its other end upon the long 7 end of a lever 7 which is fulcrumed at S and has its short end 9 connected with an additional thermostatic rod 10 which is immovably supported at 11 upon the scale lever. In order to sustain the lever 1 upon the toe piece 3, it has also been the practice to provide an offset end 12 upon the lever 1 overhanging the toe ,piece 3 and resting thereon, while the toe piece 3 rests, usually through the medium of a transverse knife edge 13, in an agate 14 in the connector 4.

According to the present invention, the bearing between the toe piece 3 and the lever 1 is constructed on the ridge and groove principle, with the bearing line extending in :he direction of the toe piece adjustment. which is in the direction of length of the lever 1, the groove member of such bearing being preferably mounted on the overhanging end 12 of the lever 1 and consisting of an agate 16, while the ridge 15 is developed by suitably shaping the toe piece 3. In order to mount the groove member or agate 16 on the lever 1, the overhanging end 12 may be provided with a bore or recess 17 conveniently formed at the time of drilling the lever for the reception of other parts, and the agate may be set therein with initial rotary adjustment to align its bearing groove with the direction of toe piece adjustment, and with subsequent fixing of the agate by means of a filler 18 of plastic material.

Toe piece 3 is secured to the end of the thermostatic rod 6 so as to respond to the movements developed by the expansion and contraction of said rod, augmented by the expansion and contraction of the rod 10 multiplied in the rod 6 through means of the lever 7. The means for securing the toe piece 3 to the rod 6 is preferably a single screw 19, as this admits of a substantial angular movement of the toe piece relative to the rod and to the stirrup 4 in securing a firm bearing of its downwardly presented transverse knife edge 13 in the stirrup; moreover, the pivotal connection 6 between the opposite end of the rod 6 and lever 7 leaves the toe piece tree to thus adjust itself. This action will be appreciated upon coinparing Figure 5 with Figure 1. The hearing between the toe piece 3 and lever 1, while confining the toe piece against lateral displacement, without friction in addition tothat which is'incident to the load which it supports, permits the toe piece to rock laterally upon its ridge 15, thereby permitting its transverse knife edge 13 to rest uniformly in the groove of the agate 1 1, the

rod 6 swinging with such adjustment; and the attaching screw 19 being loosened until the parts assume these correct positions and then tightened to maintain them in such positions.

I claim 1. A scale lever having a load transmiti .ting toe piece ad ustable longitudinally of mitting toe piece adjustable longitudinally of the lever, and a ridge and groove bearing through which the lever transmits its load to the toe piece, extending in the direction 01 the length of the lever and permitting movement of the toe piece relatively to the lever inrsaid direction while resisting its displacement transversely thereto; the groove of the bearing being greater than the ridge in transverse dimension and restricting the surface of contact substantially to a line.

3. A scale lever having at its free end a load transmitting toe piece, a ridge and groove bearing throughl which the levier transmits its load to the toe piece, said bearing being located with its ridge extending groove bearing through which the lever and permitting longitudinal but resisting transverse movement of the toe relatively 'to the lever, and means for moving the toe piece in said direction, to change the length of the lever.

4. A scale lever having at its free end a load transmitting toe piece, and a ridge and groove bearing through which the lever transmits its load to the toe piece, said bean ing being located with its ridge extending in the direction of the length of the lever and permitting longitudinal but resisting transverse displacement of the toe piece relatively to the lever, and means for imparting longitudinal movement to the toe piece, which means permits the toe piece to rock on the lever.

5. A scale lever having at its free end a load transmitting toe piece, a ridge and groove bearing through i which the lever transmits its load to the toe piece, said bearing being located with its ridge extending in the direction of the length of the lever and permitting longitudinal but resisting transverse displacement of the toe piece relatively to the lever, means for imparting longitudinal movement to the toe piece, and means connecting said movement imparting means with said toe piece that permits the latter to turn relatively to the former and rock upon the lever. V

r 6. In a weighing scale, a lever constructed with a groove extending in the direction 0 the length of the lever, a load transmitting toe-piece, constructed with an" edge resting in said groove, and adjustable longltudinally of the lever by sliding its edge in said groove, and means for imparting such adjusting movement to said toe-piece.

T. In a weighing scale, a lever member, a load transmitting toe-piece member,adj'ustable longitudinally of the lever member to change the length of the latter, one of said members being constructed with a groove and the other with an edge coinciding with the apex of said groove, said edge and groove lying in the direction of the length of the lever and the one sliding on the other in the adjustment of the toe-piece member, a thermostatic member for imparting such adjustment, and means connecting said thermostatic member with said toe-piece memher, which leaves the toe-piecemember tree to rock transversely of and assume its proper angle upon the lever.

8; In a scale, a lever member, a load transmitting toe-piece member, means impartingadjustment to said toe-piece member longitudinally of said lever member to change theIeverage through which load is transmitted, a ridge-part carried by one of said members and a groove-part carried by the other of said members; said groove-part receiving said ridge-part and providing the bearing upon which said adjustment takes place; one ofsaid members being constructed with a recess which receives the part which it carries, with freedom of rotary adjustment of its said part in the assembly of the members, and thereby insuring coincidence of the ridge and groove.

9. In a scale, a lever member, a. loadtransmitting toe-piece member having longitudinal adjustment thereon for changing the leverage through which the load is transmitted, a ridge part carried by one of said members, a groove part carried by the other of said members, the ridge and groove of said parts sliding, the one in the other,

, in the adjustment of the toe-piece member,

one of said members being constructed with a recess in which it receives the said part which it carries, with freedom of rotary adjustment at the time of original assembly of the members, thereby insuring coincidence of the ridge and groove, and a plastic filling in said recess which holds the part received therein in the position which it assumes. V

7 10. In a Weighing scale, the combination of a lever member, a longitudinally adjustable load transmitting toe-piece member, one of said members being provided with a groove and the other with a coacting ridge, through the medium of which the toe-piece member bears against the lever member, said ridge and groove extending in the direction of the length of the lever member, and permitting sidewise rocking movement and lengthwise sliding movement of the toepiece member upon the lever member, and a load transmitting stirrup, said toe-piece member and stirrup being constructed, one with a ridge and the other with a groove, through the medium of which they bear one against the other; the last named ridge and groove extending in a direction transverse to that of the ridge and groove first named.

11. In a weighing scale, the combination of a lever member, a longitudinally adjustable load transmitting toe-piece member, one of said members being provided with a groove and the other with a coacting ridge, through the medium of which the toe-piece member bears against the lever member, said ridge and groove extending in the direction of the length of the lever member, and permitting sidewise rocking movement and lengthwise sliding movement of the toe-piece member upon the lever member, and a load transmitting stirrup, said toe-piece member and stirrup being constructed, one with a ridge and the other with a groove, through the medium of which they bear one against the other; the lastnamed ridge and groove extending in a direction transverse to that oftheridge and groove first named; and a thermostatic member which imparts longitudinal adjusting movements to the toepiece member relatively to the lever member.

12. In a weighing scale, the combination of a lever member, a longitudinally adjusta ble load transmitting toe-piece member, one of said members being provided with a groove and the other with a coacting ridge, through the medium of which the toe-piece member bears against the lever member, said ridge and groove extending in the direction of the length of the lever member, and permitting sidewise rocking movement and lengthwise sliding movement of the toepiece member upon the lever member, and a load transmitting stirrup, said toe-piece member and stirrup being constructed, one with a ridge and the other with a groove, through the medium of which they bear one against the other; the last named ridge and groove extending in a direction transverse to that of the ridge and groove first named; a thermostatic member which imparts longitudinal adjusting movements to the toe-piece member relatively to the lever member, and means positively connecting said toe-piece member with said thermostatic member, which transmits expansion and contraction movements of the thermostatic member as opposite sliding move ments in the toepiece member and permits transverse rocking movements of the toepiece member on the lever member.

13. In a weighing scale, a lever member, and a toe-piece member constructed, one

i laterally and slide longitudinally on the lever member, a stirrup coacting with said toe-piece member in transmitting load, said stirrup and toe-piece member being constructed, one with a ridge and the other with a groove, transverse to the ridge and groove first named, and providing the load transmitting bearing between the stirrup and toe-piece member, a thermostatic bar extending longitudinally of the lever, means connecting one end of the thermostatic bar with the toe-piece member, imparting longitudinal sliding movement to the toe-piece member, but permitting it to turn relatively to the thermostatic bar as it rocks on the lever-member, and means pivotally supporting the other end of the thermostatic bar upon the lever member. v

14. In a scale, aload transmitting connector, a toe piece having a transverse ridge and groove bearing in said connector, a lever having a longitudinal ridge and groove bearing on said toe piece, permitting adjustment of the toepiece in the direction of the length of the lever, and an adjusting rod carried by the lever and connected with said toe-piece independently of the longitudinal ridge and groove bearing.

15. In a scale, a load transmitting connector, a toe-piece havinga transverse ridge and groove bearing in said connector, a lever having a longitudinal ridge and groove bearing on said toe-piece, permitting adjustment of the toe-piece in the direction of the length of the lever, and an adjusting rod carried by the lever and connected with said toe-piece independently of the longitudinal ridge and groove bearing; said adjusting rod being pivotally secured to the lever at its end remote from said toepiece.

16. In a scale, a load transmitting connector, a toe-piece having a transverse ridge and groove bearing in said connector, a lever having a longitudinal ridge and groove bearing on said toe-piece, permitting adjustment of the toe-piece in the direction of the length of the lever, and an adjusting rod carried by the lever and connected with said toe-piece independently of the longitudinal ridge and groove bearing; the connection betweenthe adjusting rod and the toe-piece permitting the toe-piece to rock in its longitudinal ridge and groove bearing in seating the toe-piece in the connector.

17. In a scale, a load transmitting connector, a toe-piece having a transverse ridge and groove bearing in said connector, a lever having a longitudinal ridge and groove bearing on said toe-piece, permitting adjustment of the toe-piece in the direction of the length of the lever, and an adjusting rod carried by the lever and connected with said toe-piece independently of the longitudinal ridge and groove bearing; the connection between the adjusting rod and the toe-piece permitting the toe-piece to rock in its longitudinal ridge and groove bearing in seating the toe-piece in the connector, and the adjusting rod being supported at one end by the toe-piece and having a pivotal support at its end remote from the toe-piece.

Signed at Chicago, Illinois, this 1st day of June, 1923.

GEORGE M. LUDLOW. 

